This invention relates to absorbent tampons. More particularly, the invention relates to a tampon having improved leakage protection and comfort through improved expansion characteristics.
A wide variety of absorbent catamenial tampons have long been known in the art. Most currently commercially available tampons are made from a tampon pledget which has been compressed into a substantially cylindrical form. Tampon pledgets of a variety of types and constructions have been described in the art. Prior to compression, the tampon may be rolled, spirally wound, folded, or assembled as a rectangular pad of absorbent material. Tampons made from a generally rectangular pledget of absorbent material have been popular and successful in the market.
The absorbent catamenial tampons now in use are typically formed from batts larger in size than the vaginal orifice, which are then compressed into a rigid cylindrical pledget in order to facilitate insertion. As fluid is absorbed, these compressed tampons are expected to re-expand toward their original pre-compressed size, and to eventually become large enough to effectively cover the vaginal cavity against fluid leakage or bypass. While it has been found that these compressed tampons perform their intended function tolerably well, even the best of them do not always re-expand sufficiently to provide good coverage against leakage while providing comfortable wear.
A compressed tampon, to perform well, should re-expand with enough force to provide the best possible anatomical fit. Nevertheless, these needs are not always consistent with the desire to provide a tampon which is comfortable to the wearer. It has been long recognized that the internal vaginal cavity in its normal collapsed state is wider in its transverse dimension than in its anterior/posterior dimension. Additionally, nerve sensitivity is higher in the anterior/posterior dimension than in the transverse dimension. Thus, it is desirable when considering a tampon for catamenial use, to provide a structure which expands enough (with sufficient force), particularly in the transverse dimension, to contact substantially all of surface of the vaginal walls from one side to the other in the vaginal cavity to prevent early bypass of the menstrual discharges from the cervix. It is also desirable to provide a comfortable tampon which provides the minimal necessary force in the anterior/posterior dimension to maintain acceptable comfort.
Prior art tampons, therefore, attempted to balance these design objectives as best as possible, often having to trade some performance with respect to one objective for improved performance with respect to another. Many currently marketed tampons, particularly rolled or spiral wound which are then compressed radially (i.e. compressed from the sides essentially uniformly in all dimensions) expand with the same transverse dimension force as anterior/posterior dimension force. These tampons do not advantageously leverage the anatomical differences of the vaginal cavity to provide maximum protection with maximum comfort since increasing the expansion forces in one dimension necessarily increases the expansion forces in the other dimension. Even those currently marketed tampons which exhibit transverse dimension forces which are greater than the anterior/posterior dimension forces may not always expand sufficiently, particularly in the transverse dimension, to provide superior coverage.
It is, therefore, desirable to provide a tampon with an improved balance of expansion force characteristics. Such a tampon should not introduce new drawbacks, such as a decreased comfort while wearing the tampon or decreased ability to comfortably remove the tampon. Ideally, such a tampon should be able to be manufactured out of materials similar to those currently used for tampons. These materials have the advantages of a proven record of suitability for human use, acceptable cost, and the ability to be manufactured into tampons without undue modifications to current commercially available manufacturing equipment.
This invention relates to catamenial tampons, and more particularly, to tampons having particularly desired expansion force characteristics. The tampons of the present invention comprise a mass of absorbent material which is fluid expanding. The tampons exert an X Dimension Force of at least about 400 grams, and a Z Dimension Force of less than about 200 grams. Alternatively, the ratio of the X Dimension Force to the Z Dimension Force is from about 5 to about 50.